1. Field of the Disclosure
The present invention relates to a display device with an embedded touch panel, and more particularly to a display device with an embedded touch panel which does not require a Flexible Printed Circuit (FPC) for applying a shielding signal to a shielding electrode and thus results in reducing the manufacturing cost and simplifying the fabrication process.
2. Discussion of the Related Art
Various image display devices include, for example, cathode ray tubes CRT, liquid crystal display devices LCD, plasma display panel devices PDP, electro luminescence display devices ELD, and organic luminescence display devices. Of these display devices, the LCD device controls light transmissivity of liquid crystals by using an electric field to display a picture. For this, the liquid crystal display device is provided with a liquid crystal panel having liquid crystal cells, a backlight unit for directing a light to the liquid crystal panel, and a driving circuit unit for driving the backlight unit and the liquid crystal cells.
There has been a rapid increase of demands for a display device which also can be used as an input device by mounting a touch panel thereto, where a surface of a liquid crystal panel is pressed down with a pointer (a user's finger) to input information pertinent to the pointed position. Depending on touch sensing types, the touch panels are classified into a resistance type, a capacitive type, and an infrared ray sensing type. Recently, the capacitive type is paid attention in view of convenience of fabrication, sensing capability, and so on. The touch panel is provided with a sensor glass having electrodes formed thereon for sensing the touch by a capacitive system, and a cover glass arranged to face a sensor substrate.
In the meantime, since the touch panel is mounted to the liquid crystal panel, there has been a problem in that noise can infiltrate into the liquid crystal panel from the touch panel. And, since a signal being applied to the touch panel affects a signal being applied to the liquid crystal panel, interference between the signals take place. In order to shield the noise infiltrating into the liquid crystal panel and preventing the signal interference between the liquid crystal panel and the touch panel from taking place, a shielding electrode is formed on a back side of the touch panel.
As shown in FIG. 1, the shielding electrode 1 is formed on the back side of the touch panel 2, and a shielding signal supply line 3 is formed on a top side of the touch panel 2. Also, an additional FPC (Flexible Printed Circuit) 4 connects the shielding signal supply line 3 with the shielding electrode 1. As a ground signal is applied to the shielding electrode through the shielding signal supply line 3 and FPC 4, the noise infiltrating into the liquid crystal panel is shielded. In order to apply the ground signal to the shielding electrode, however, the FPC (Flexible Printed Circuit) 4 FPC mounted to the underside of the shielding electrode is required. Consequently, the number of FPC increases, increasing cost and to cause a fabrication process complicate.